High Strength Steel Applications in Hydropower, Penstock Steel Specifications and Quality Control

Abstract

Only 20 years ago most structural and plate steels in common use on hydro power projects had a yield point in the region of 28 ksi to 36 ksi. Now we have a multiplicity of steels with yield points ranging from 30 ksi to over 100 ksi, with the design engineer having to face the problem of which steel should be used in a particular application. Furthermore, since there are often advantages in using a high strength steel, the designer is faced with having to care fully consider the design conditions and steel properties other than the yield point, since the yield point is not the only measure of strength. In this paper I will outline some of the practical considerations which must be taken into account, confining the subject to use of intermediate and high strength steels in penstocks and turbine spiral casings, since this is by far the major area where such steels are used on power projects.